Heat cycles

DUNLOP-RTS

New Member
Now lets tackle the issue of HEAT CYCLES.


Heat cycling of the tire is a very confusing and misunderstood area. I will say that I have heard that other brands are well known for "going off" or "heat cycling" and I will leave that conversation to another thread another day.

For now I'm going to stick with Dunlop's, as that is what I know.

Do tires heat cycle? Yes

Is this the most important factor in tires? NO! in fact it is NOT very significant, and very over emphasized.

Certainly making a tire go from 250 deg to negative 10 deg over and over is not the best thing you can do to a tire, but consider that placing it on a warmer, at 190 deg, for 8 hours is not any better. Both extremes are not the best for the tire.

We all hear about "Heat Cycle", but almost never do we hear talk about the thickness of the tire, or tread depth/wear.

Fact: :idea:The thicker the tread rubber, the more grip. The thinner the tread rubber, the less grip. As you ride on the tire, session after session, the rubber is getting thinner and there is less and less grip. Often this is mistaken for "heat cycle", and the rider now places his attention on his warmers and not on the real important factor of how much tread rubber is left on his tire.

Odd rituals start to crop up regarding tire warmers: Riders come back to the pits and RUSH to put their warmers on and crank them up to full, all in an attempt to "stop the heat cycle!". When buying used tires, riders mistakenly rate the tire by how many heat cycles it has, not the tread depth.

It is a mistake to emphasize heat cycling over tread depth, with Dunlops.




You can use a D211GPA or any other Dunlop tire without warmers and have no problems. ( Make sure you do heat the tire up for the first couple laps before you get with the pace.)

You might have a very small decrease in grip or life, but that would be very small and most likely not noticeable over the 1-5 track days you will get out of the tires. You would be splitting hairs on the performance level and tire life with/without warmers. Even if you were to do back to back tests, you would find that if in just 1 session in the life of the tire, you went 5 seconds faster, that would make more of a difference than heat cycling because you used more tread rubber in that session.

Heat cycles are not a total myth, but they do not make as big a difference as the internet would lead you to believe.

Tire warmers are good thing to have if you want to get going right out of the pits. They are not a requirement. Note that our recommendation for track day warmers has you putting the warmers on after a session and not plugging them in right away. This is so you don't needlessly force heat into the tire continuously for no reason. http://www.dunlopracing.com/Warmers.pdf :rtfm:

Ever notice that the chatter about heat cycles started about the time tire warmers became cheaper and more readily available? Do you think there could be an urban legend that started because of this increased supply? :notsure:
 

BigBird

Member
awesome post!

Heat cycles are not a total myth, but they do not make as big a difference as the internet would lead you to believe.
If its on the internet, it has to be true :eek:
 

tittys04

Member
At the info session at Barber, and also on the "warmer procedure" pdf, you mentioned that you shouldn't reset your tire pressures when you come off the track. This is opposite of what I have heard, and was wondering why that is the correct procedure.

My thinking (although probably wrong because I'm doing it wrong) is that you want your tire pressures to be accurate while riding (not just when on the warmers). Meaning... if I set the pressures after being on the warmers, and they rise during my time on the track because my tires continued to heat up, why shouldn't I re-set my pressures back to the original pressure? Isn't that the optimal operating pressure?

Thanks for your input!
 

Kegger

New Member
Yay - good info to have!

I always look at the wear bars or buttons on slicks when buying take-offs and never worried about the heat cycles. I figure if they still have meat they couldnt have been heat cycled that much anyway. Its good to know that the heat cycles really dont define a tire.

tittys04;186323 wrote: At the info session at Barber, and also on the "warmer procedure" pdf, you mentioned that you shouldn't reset your tire pressures when you come off the track. This is opposite of what I have heard, and was wondering why that is the correct procedure.

My thinking (although probably wrong because I'm doing it wrong) is that you want your tire pressures to be accurate while riding (not just when on the warmers). Meaning... if I set the pressures after being on the warmers, and they rise during my time on the track because my tires continued to heat up, why shouldn't I re-set my pressures back to the original pressure? Isn't that the optimal operating pressure?
+1?
 

fitz

New Member
DUNLOP-RTS;186289 wrote:
Fact: :idea:The thicker the tread rubber, the more grip. The thinner the tread rubber, the less grip. As you ride on the tire, session after session, the rubber is getting thinner and there is less and less grip.

Could you explain this further please?

I understand this with car/truck tire "tread" when it comes to all weather tires in the snow or rain, but with a bike tire or race tire that grip comes from outside of the tire (slicks) and only makes contact with the track within mm of the surface. So how would thickness matter? If you have half the "tread" why would that outside mm change how it grips?

Thanks

fitz
 

Meat

Member
fitz;186342 wrote: Could you explain this further please?

I understand this with car/truck tire "tread" when it comes to all weather tires in the snow or rain, but with a bike tire or race tire that grip comes from outside of the tire (slicks) and only makes contact with the track within mm of the surface. So how would thickness matter? If you have half the "tread" why would that outside mm change how it grips?

Thanks

fitz
+1!!!
 

noobinacan

Member
also,
in the tire warmer procedure doc...

4) If the bike is going sit in the pits between sessions; put the warmers on and leave unplugged. Then 20-30 minutes before your session, plug them in.
plug them in at warm /medium ?
and hot few mins before leaving pits ?
 

geekmug

New Member
fitz;186342 wrote: I understand this with car/truck tire "tread" when it comes to all weather tires in the snow or rain, but with a bike tire or race tire that grip comes from outside of the tire (slicks) and only makes contact with the track within mm of the surface. So how would thickness matter? If you have half the "tread" why would that outside mm change how it grips?
You'll notice that he never makes reference to anything but DOT race tires. I don't think his advice really applies if you are using hypersport tires. In fact, I have two sets of BT016s that completely disagree with what he said.. they both are well above the wear bars, but they are hard as a rock now. There are volatile compounds in tires that leave the tire, but DOT race tires usually wear the rubber away before the shift in chemistry of the rubber becomes a factor.

I think the OP's post needs to be revised to make clear what the context of his advice stems from (e.g., race tires).
 

Kegger

New Member
geekmug;186409 wrote: You'll notice that he never makes reference to anything but DOT race tires. I don't think his advice really applies if you are using hypersport tires. In fact, I have two sets of BT016s that completely disagree with what he said.. they both are well above the wear bars, but they are hard as a rock now. There are volatile compounds in tires that leave the tire, but DOT race tires usually wear the rubber away before the shift in chemistry of the rubber becomes a factor.

I think the OP's post needs to be revised to make clear what the context of his advice stems from (e.g., race tires).
To be fair, this is all referencing Dunlop Dot's too. Brickstones probably arent his forte, and he said he was only referencing Dunlops.
 

JRA

New Member
All tires, including slicks have tread rubber. In an effort to help out here I'll repeat exactly what I've heard Steve say more than once... If you have a chance you should attend one of the tire talks he's been giving in the Southeast this year. He's covered all of these questions with very thorough explanations.

As you use your tires you wear away the tread rubber. As you wear away the rubber the tire has progressively less grip and it runs cooler. The more rubber you have the more grip you will have and the more heat you will generate in the tire. They could make tread rubber much thicker and get a lot more grip, but the trade off would be the tire would overheat quickly and blister. The thickness they build is the sweet spot between too much and not enough.

You could take a new tire and heat it on warmers and then let it cool. You could do this once an hour many times over. What you would have in the end is still a new tire that would perform almost as well (if not just as well) as tire with no heat cycles. This would be true for the vast majority of riders. A professional rider might be able to test both and determine that one tire had more grip than the other, but most of us wouldn't know the difference.

I have a feeling this forum is going to generate a whole lot of really good information that will be easily accessible to all. I also think somebody is going to be really busy typing though. :D
 

slowpoke

New Member
Steve - When running Dunlops, I no longer follow the tire warmer recommendations during the sessions before lunchtime (or on cold days). I tend to bake the tire (warmers on high) to avoid cold tear which i was getting with warmers on medium and then high (as recommended) in the mornings.
After lunch (on warmer days), i do leave them on medium until 20 mins before the session at which point I switch them to high.

Just 1 guy's experience.
 

noobinacan

Member
slowpoke;186446 wrote: Steve - When running Dunlops, I no longer follow the tire warmer recommendations during the sessions before lunchtime (or on cold days). I tend to bake the tire to avoid cold tear which i was getting on medium w/ the warmers in the mornings.
After lunch (on warmer days), i do leave them on medium until 20 mins before the session.

Just 1 guy's experience.
ugh...now I'm confused ^ :(


and I'll throw in the compound monkey wrench in here as well...
is it true that softer compound is better for hotter days vs harder compound ? as in more grip ?
 
noobinacan;186448 wrote: ugh...now I'm confused ^ :(


and I'll throw in the compound monkey wrench in here as well...
is it true that softer compound is better for hotter days vs harder compound ? as in more grip ?
Soft for cold. Hard for hot:D

BZ
 
slowpoke;186451 wrote: not on my bike --- just the opposite for me. Hard gets greasy in hot, and soft tears easier in cold.
I am using Bridgestones, which could be the issue. should have wrtten more but using wifes ipad and typing is slow.

BZ
 

fitz

New Member
JRA;186428 wrote: All tires, including slicks have tread rubber. In an effort to help out here I'll repeat exactly what I've heard Steve say more than once... If you have a chance you should attend one of the tire talks he's been giving in the Southeast this year. He's covered all of these questions with very thorough explanations.

As you use your tires you wear away the tread rubber. As you wear away the rubber the tire has progressively less grip and it runs cooler. The more rubber you have the more grip you will have and the more heat you will generate in the tire. They could make tread rubber much thicker and get a lot more grip, but the trade off would be the tire would overheat quickly and blister. The thickness they build is the sweet spot between too much and not enough.

You could take a new tire and heat it on warmers and then let it cool. You could do this once an hour many times over. What you would have in the end is still a new tire that would perform almost as well (if not just as well) as tire with no heat cycles. This would be true for the vast majority of riders. A professional rider might be able to test both and determine that one tire had more grip than the other, but most of us wouldn't know the difference.

I have a feeling this forum is going to generate a whole lot of really good information that will be easily accessible to all. I also think somebody is going to be really busy typing though. :D
Thanks for the response John, I suppose when you start delving deeper into tire technology only those that are able to comprehend and manipulate magic understand it.

fitz
 
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